[Libguestfs] [PATCH] builder: Allow GnuPG v2 or v1 to be used (RHBZ#1438939).

[Richard W.M. Jones]

All of the GPG commands we run are compatible with either v1 or v2, so
this simply involves changing the configure script to find either
binary.
---
 builder/cmdline.ml         |  2 +-
 docs/guestfs-building.pod  | 17 ++++++++++++++++-
 m4/guestfs_progs.m4        | 19 +++++++++++++++++++
 mllib/guestfs_config.ml.in |  1 +
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/builder/cmdline.ml b/builder/cmdline.ml
index aa852e8f5..5424e885a 100644
--- a/builder/cmdline.ml
+++ b/builder/cmdline.ml
@@ -87,7 +87,7 @@ let parse_cmdline () =
   let add_fingerprint arg = push_front arg fingerprints in
 
   let format = ref "" in
-  let gpg = ref "gpg" in
+  let gpg = ref Guestfs_config.gnupg in
 
   let list_format = ref List_entries.Short in
   let list_set_long () = list_format := List_entries.Long in
diff --git a/docs/guestfs-building.pod b/docs/guestfs-building.pod
index 5e314b34d..b29fcc4ab 100644
--- a/docs/guestfs-building.pod
+++ b/docs/guestfs-building.pod
@@ -280,10 +280,25 @@ Optional.  For the L<UML backend|guestfs(3)/BACKEND>.
 
 Optional.  Used by virt-builder for downloads.
 
-=item gpg
+=item GNU Privacy Guard (GnuPG, gpg) v1 or v2
 
 Optional.  Used by virt-builder for checking digital signatures.
 
+Either version 1 or version 2 or fallback from v2 to v1 may be used by
+specifying:
+
+ ./configure --with-gnupg="gpg"
+
+ ./configure --with-gnupg="gpg2"
+
+ ./configure --with-gnupg="gpg2 gpg"
+
+Additionally the end user can override the choice using the
+virt-builder I<--gpg> option.
+
+B<NB:> Do not confuse C<gpg2> with C<gpgv2>.  The latter is for
+B<v>erifying signatures only, and will not work as the gnupg binary.
+
 =item liblzma
 
 Optional.  If available, virt-builder will use this library
diff --git a/m4/guestfs_progs.m4 b/m4/guestfs_progs.m4
index 1f0a4c1f6..ec1f400e9 100644
--- a/m4/guestfs_progs.m4
+++ b/m4/guestfs_progs.m4
@@ -114,6 +114,25 @@ if test "x$YACC" = "xyacc"; then
     AC_MSG_FAILURE([GNU 'bison' is required (yacc won't work).])
 fi
 
+dnl Check for GnuPG, used by virt-builder.  This is just the
+dnl default binary, and it can be overridden on the command line.
+AC_ARG_WITH([gnupg],
+    [AS_HELP_STRING([--with-gnupg="gpg2"],
+        [set default GNU Privacy Guard binary v1 or v2 @<:@default="gpg2 gpg"@:>@])],
+    [],
+    [with_gnupg="gpg2 gpg"]
+)
+
+AS_IF([test "x$with_gnupg" = "xno"],[
+    AC_MSG_WARN([GnuPG was disabled, you must use virt-builder --gpg option to check signatures])
+    GNUPG=no
+],[
+    AC_PATH_PROGS([GNUPG],[$with_gnupg],[no])
+    AS_IF([test "x$GNUPG" = "xno"],[
+        AC_MSG_WARN([GnuPG was not found])
+    ])
+])
+
 dnl zip/unzip, used by virt-v2v
 AC_PATH_PROGS([ZIP],[zip],[no])
 AC_DEFINE_UNQUOTED([ZIP],["$ZIP"],[Name of zip program.])
diff --git a/mllib/guestfs_config.ml.in b/mllib/guestfs_config.ml.in
index 4d1a5c5d0..68dbcbc20 100644
--- a/mllib/guestfs_config.ml.in
+++ b/mllib/guestfs_config.ml.in
@@ -23,3 +23,4 @@ let package_version_full = "@PACKAGE_VERSION_FULL@"
 let prefix = "@prefix@"
 let datadir = prefix ^ "/share"
 let host_cpu = "@host_cpu@"
+let gnupg = "@GNUPG@"
-- 
2.12.0